The sorting of articles by a wide variety of different properties, while transporting the articles, is becoming ever increasingly desirable, especially for supplying produce to grocery stores and supermarkets. Increasingly popular are color sorting systems for apples and like pieces of fruit, such as shown in WO 91/04803. However, as recognized as desirable by that reference, and as still not achieved by the art, is the ability to see the entire apple or other piece of fruit as it is being transported, and not to see significantly less than the whole apple, or see parts of the apple twice.
When an apple is being conveyed into association with color sensing equipment, such as a color camera, the apple must be rotated in an attempt to allow the camera to see the entire apple. However, depending upon the size of the apple, the rotation that is provided by conventional rollers on support elements is less than desirable. Existing equipment can rotate smaller apples carried thereby much more than 360.degree. so that some parts of the apple are seen twice by the camera, while larger apples are rotated much less than 360.degree., so that not all of the apple is seen. This can result in a false impression of what the true average color of the apple is, resulting in mis-sorting of applies.
Another problem that can contribute to imprecise rotation of the apples in association with the color sensing equipment is a less than precise drive for rotating the apples when in operative association with the color sensing equipment. For example, such as shown in U.S. Pat. Nos. 5,101,982 and 5,267,654, the rollers carrying the apples may be rotated by a wheel or an extension of a shaft supporting the rollers, by engaging the flat surface. Depending upon contaminant buildup, frictional forces, or other factors, this rotation may not be precise.
According to the present invention an assembly and method are provided which allow the precise rotation of apples, or like articles to be sorted, regardless of the size (within reason) of the apples being sorted. By providing precise rotation of the apples, especially in association with color sensing equipment, it is possible to insure that the color sensing equipment sees all of the apple, within plus or minus 15.degree. or less (typically 5.degree. or less), so that a true picture is given of the apple and it may be accurately sorted. This desirable result is accomplished in two ways. One way is by using particularly tapered cones rather than rollers for supporting the fruit or other articles being transported, and secondly by providing a gear attached to each shaft supporting the cones, which cooperates with a stationary rack.
The invention also deals with another problem that can occur in the prior art when using rollers, such as in U.S. Pat. Nos. 5,101,982 and 5,267,654, as well as in WO 91/04803. In systems such as shown in these references there may be a tendency for an apple, or other article, to move from one set of rollers to the next, which has a significant adverse impact on the proper transport and sorting of the articles. The invention also essentially solves that problem by a bumper at the leading and trailing portions of each support element supporting two sets of cones.
The invention is also advantageous since it can utilize pre-existing sorting mechanisms and support elements, so that a minimum amount of re-tooling, and/or additional manufacturing procedures, are necessary to construct the assembly according to the invention. Particularly, the assembly according to the present invention may be made merely by modifying the support elements shown in U.S. Pat. No. 5,183,151 (the disclosure of which is hereby incorporated by reference herein).
The invention is further advantageous in providing a substantially constant degree of rotation of an article being sorted per revolution of the supporting elements (cones). According to the invention articles (e.g. pieces of fruit, such as apples) having a diameter of about 2 1/4-31/2 inches are rotated approximately 120.degree. for each 360.degree. rotation of the input shaft.
According to one aspect of the present invention an article transporting assembly is provided comprising the following components: A support element mounted for movement in a first direction. Two sets of cones mounted to the support element by rotatable shafts, each set comprising first and second cones having a tapered exterior surface, the cones on each shaft facing each other and tapering to an imaginary substantially common midpoint. And the cones for supporting an article essentially without the article touching the shafts, and for rotating the article upon rotation of the shafts. Each of the cones preferably has a first angle of taper of between about 25-35.degree.(e.g. about 28.degree.). The cones may be made of a soft, yieldable material, such as a soft plastic, so that the fruit is not bruised when carried thereby, but yet the cones have sufficient rigidity and structural integrity so as to properly support the articles during transport and rotation.
Typically, the support element is mounted for movement by a conveyor chain, the conveyor chain connected to a plurality of other like support elements in an endless assembly. Typically a bumper is provided at each of the leading and trailing portions of each support element in the first direction, to substantially prevent an article supported by the cones from moving from one support element to the next. Each cone has a portion distal from the cone of the shaft, and the distal portion may have a second angle of taper which is greater than the first angle of taper by at least about 5.degree., so that a large article may be supported substantially only by the distal portions. Any number of such angles may be provided, depending upon the type of fruit or other articles that is expected to be encountered.
The article transporting assembly according to the invention also typically further comprises means for positively rotating the shafts, substantially in unison, as the support element moves in the first direction. The means for positively rotating the shafts may comprise any conventional structure that is capable of performing that function, such as a roller connected to a first end of each of the shafts and a substantially stationary track which engages the rollers so that the rollers rotate with respect to the track. In a preferred embodiment according to the invention, however, the rollers are gears, and the track comprises a rack having teeth which cooperate with the gears. Preferably the rack is of a material that will wear out faster than the gears, so that the rack needs to be replaced more often than the gears since the rack replacement is easy and gear replacement is much more difficult. For example, the gears may be made of Delrin.RTM., or a like wear-resistant plastic, while the rack is made of rubber, or synthetic rubber, so that the rack has one-half or less the effective life as the effective life of the gears, so that the rack wears out at least about twice as fast as the gears. The gears and rack teeth may be dimensioned so that one turn of the gear effects substantially a 120.degree. rotation of an article supported by the cones.
As shown in U.S. Pat. No. 5,183,151, the assembly further comprises means for tilting the support element sideways to pivot about a substantially horizontal axis substantially perpendicular to the first direction, to discharge articles supported by the cones, to sort the articles into groups (by weight or color, but preferably considering both weight and color). Preferably the shafts are mounted with vertical lost motion to the support element. The assembly also preferably further comprises color sensing equipment cooperating with the support element for determining the color of articles supported by the cones as the shafts rotate, the color sensing equipment cooperating with the tilting means to effect color sorting of articles transported by the support elements. The assembly may also further comprise weighing means over which the support elements pass; and may further comprise means for tilting the support element sideways to pivot about a substantially horizontal axis substantially perpendicular to the first direction to discharge articles supported by the cones, to sort the articles into groups based upon weight (and typically also color) sensed by the weighing means.
According to another aspect of the present invention an article transporting assembly is provided comprising: A support element mounted for movement in a first direction. Two sets of cones mounted to the support by rotatable shafts. The support element mounted for movement by a conveyor chain, the conveyor chain connected to a plurality of other the support elements in an endless assembly. An enlarged gear mounted on a first end of each shaft. And a substantially stationary rack having teeth engaging the gears and cooperating with the gears to effect rotation of the shafts as the support element is moved in the first direction. The details of the gears and rack teeth, and the utilization of appropriate tilting means and color sensing equipment, and the like, preferably are as provided above.
According to another aspect of the present invention a method of transporting pieces of fruit (such as apples) using a support element as described above is provided. The method comprises: (a) Feeding pieces of fruit into contact with the cones while moving the support element in a first direction. (b) Supporting a piece of fruit on the cones, essentially not supported by the shaft, while the support element moves in the first direction. And (c) substantially positively preventing a piece of fruit mounted on the cones from moving onto another support element in series with the support element.
The method may further comprise: (d) passing the support element into operative association with color sensing equipment; (e) rotating the piece of fruit a precisely determined amount by rotating the shafts mounting the cones, while the fruit is in operative association with the color sensing equipment; and (f) sorting the fruit depending upon the color (and also perhaps weight) sensed by the color sensing equipment by pivoting the support element about a substantially horizontal axis substantially perpendicular to the first direction at one of several possible locations. Where the fruit has a diameter of between about 21/4-31/2 inches, (e) is practiced so as to rotate each piece of fruit substantially 120.degree. for a 360.degree. rotation of the shafts.
It is the primary object of the present invention to provide an effective article transporting assembly, and method of transporting and/or sorting articles such as pieces of fruit, which provides precise rotation of the articles during transport. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.